In recent years, as a high capacity optical disc, a Blu-ray Disc™ (BD) (hereinafter referred to as “high capacity optical disc”) has been commercially available. The high capacity optical disc realizes a recording capacity of about 25 GB with a light wavelength for recording and reproducing of about 405 nm and a numerical aperture NA of about 0.85 of a collecting lens for a recording and reproducing optical system.
In the high capacity optical disc type optical recording medium, a wide variety of write-once recording layer materials have been considered. As the conventional write-once optical disc recording layer materials, organic dye materials are known. Meanwhile, in order to improve the productivity of the use of the organic dye materials and a problem concerning long-term storage stability of recording signals, a wide variety of inorganic materials used for the write-once recording layer materials have been considered. For example, Patent Document 1 below proposes an optical recording medium having a recording layer including Te—O or the like that is crystallized at a high speed with rising temperature and generates an optical change.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2008-112556